Metering valves are used as injection valves, for example in the case of direct injection of petrol or in the case of direct injection of diesel, in order to supply an internal combustion engine of a motor vehicle with a precisely metered quantity of fuel. In the case of modern injection valves, piezoactuators are used for controlling a nozzle needle. Piezoelectric multilayer actuators which are currently available were developed for the common rail injection system and have high blocking forces of up to 2000 Newton with a small extension of up to 60 μm.
For a direct actuation of the nozzle needle in a petrol injection valve, an adjusting path of up to 100 μm with a correspondingly smaller force is necessary. The piezoactuators which are already available therefore do not correspond.
Furthermore, thermal expansions, aging effects in the piezoceramic and pressure-induced expansions, in particular at small deflections of up to 60 μm, have a negative effect on the correct setting of the nozzle needle.